Molecular specificity recognition

Despite the consistent picture of a controlled protein monolayer formation by molecularly specific "recognition" reactions deduced from the optical data we were still concerned about the limited optical resolution. In order to further enhance the special resolution euid to observe the binding of streptavidin to a functionalized surface (eventually) with molecular resolution we performed atomic force microscopic (AFM) studies at a membrane/solution-interface. In Fig.6 the experimental situation is schematically sketched. Prior to the protein injection a lipid monolayer with coexisting fluid and ordered domains deposited onto a condensed monolayer on the mica substrate has to be imaged by scanning the tip across the membrane surface. It is well-known that a fluid membrane can not stand the load of the tip (even at a reduced force) so that we expect a height contrast between the two areas of about a monolayer thickness... 

It is well known that a very important feature of many biological systems is specific recognition at the molecular level. Antibodies as a group are widely used for molecular recognition, e.g., affinity assays. This feature can be used by labeling an anti-human growth hormone antibody fraction with a fluorescent tag... 

Allain FH, Bouvet P, Dieckmann T, Feigon J (2000a) Molecular basis of sequence-specific recognition of pre-ribosomal RNA by nucleolin. Embo J 19 6870-6881... 

Polymer-mediated self-assembly of nanoparticles provides a versatile and effective approach for the fabrication of new materials. This bottom-up strategy builds up nanocomposite materials from diverse nanosized building blocks by incorporation of molecular-level recognition sites. The flexibility and reversibUity of self-assembly processes imparted by specific molecular interactions facilitates the formation of defect-free superstmctures, and it can be further explored in fields ranging from electronics to molecular biology. 

The cyclosome (or APC) is a high molecular weight complex that degrades proteins containing a specific recognition sequence, the destruction box (see chapter 13.2.4). Substrates are cell cycle regulators as e.g. cyclins, kinase inhibitors and spindle-associated proteins. Importantly, some forms of the cyclosome require phosphorylation in order to be active (fig. 2.15B). It is still unclear which of the many subunits carries the E3 enzyme activity. 

Fig. 11 Schematic representation of the molecular imprinting of trypsin using a polymerizable inhibitor as an anchoring monomer. The enzyme is put into contact with the anchoring monomer and co-monomers (a) polymerization is conducted (1) a cross-linked polymer is molded around the substrate binding site (b) the enzyme is removed (2), revealing a specific recognition site with inhibitory properties (c). Reproduced with permission from [108], Copyright 2009 American Chemical Society...

The technique of molecular imprinting was successfully used to create a polymer with specific recognition sites. [9] A template was used to organise monomers during the polymerisation process. After the polymerisation, it was washed away from the insoluble network, leaving behind domains of complementary size and shape (Scheme 10). 

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